Experimental and Numerical Study of the Effect of Double Row Slot Injection Locations on Film Cooling Performance of a Corrugated Surface

Based on experimental and numerical studies the present work proposes an effective injection configuration for film cooling applications on sinusoidal corrugated surfaces. The experimental study is performed for different double-row injection locations (per wavelength) viz. (L-0-L-25), (L-0-L-50), (L-0-L-75), (L-25-L-50), (L-25-L-75) and (L-50-L-75) on the sinusoidal corrugated surface at blowing ratio (1), fixed injection angle (45 degrees), and density ratio (1.095). The numerical study is conducted for a wide range of operating parameters such as blowing ratios on (0.5-2), and density ratios (1.095, 1.5, and 2.5). To access the effect of corrugation geometry three different amplitude to wavelength viz. 0.05, 0.075, and 1 are considered in the present numerical study. The outcome of the present double-row slot injection investigations on the sinusoidal corrugated surface indicates that the flow pattern and film cooling strongly depend on secondary injection locations. The (L-50-L-75) injection case shows the best performance among all selected cases. It shows a 15-19% improvement in film cooling effectiveness (average over one wavelength). The increase of amplitude to wavelength ratio is reported to be a detrimental effect and decreases the film cooling effectiveness. The increase of corrugation amplitude to wavelength ratio increases the depth of the corrugation valley, further restricts the coolant spread, and promotes coolant mixing with hot mainstream. The coolant injection in mainstream flow was also found to be a distinct impact on flow and the nondimensional velocity profile. Apart from that a significant impact of the blowing ratio and density ratio is reported.